High strength glue formulation

ABSTRACT

A pourable glue formulation is provided. The pourable glue formulation includes a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; propylene glycol; an ester alcohol; a biocide; a crosslinking agent; a defoamer; and a viscosity modifier.

This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/252,921 filed on Oct. 19, 2009, and entitled “High Strength Glue Stick”, the disclosure of which is hereby incorporated by reference herein in its entirety and made part of the present U.S. utility patent application for all purposes.

BACKGROUND OF THE INVENTION

The described invention relates in general to a glue or adhesive formulation, and more specifically to a two-part polyurethane, pourable glue formulation. Some commercially available glue products such as glue sticks typically include PVP (polyvinylpyrrolidone) or modified-PVOH (polyvinyl alcohol) polymers. These polymers provide such glue products with the strength required to adhere paper items to one another, but lack the adhesive capacity to join other more difficult materials such as wood, metal and plastic. With regard to pourable glue products, current water-based wood glues utilize PVAc (polyvinyl acetate) for adhering wood substrates to one another. When adhesion is required for non-wood substrates, either a two-part epoxy or a one-part polyurethane adhesive is typically used.

Waterborne urethane polymers are sometimes used as a base for products such as waterproof stains or clear shellacs. However, these polymers are not typically used for arts and crafts applications despite the fact that polyurethanes have a greater range of adhesion than many of the polymers used to formulate the glues and adhesives discussed above. Therefore, there is an ongoing need for a high-strength glue formulation for joining wood, metal and plastic, wherein the glue formulation includes waterborne polyurethanes.

SUMMARY OF THE INVENTION

The following provides a summary of certain exemplary embodiments of the present invention. This summary is not an extensive overview and is not intended to identify key or critical aspects or elements of the present invention or to delineate its scope.

In accordance with one aspect of the present invention, a pourable glue formulation is provided. This pourable glue formulation includes a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; a compound operative to provide freeze-thaw stability to the formulation; a compound operative to confer film-forming properties to the formulation; a compound operative to limit the growth of microorganisms in the formulation; a compound operative to provide additional final strength to the formulation; a compound operative to provide a desirable final viscosity to the formulation; and a compound operative to prevent the formulation from foaming during mixing of the ingredients therein.

In accordance with another aspect of the present invention, a pourable glue formulation is provided. This pourable glue formulation includes a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; a compound operative to provide freeze-thaw stability to the formulation; an ester alcohol; a biocide; a crosslinking agent; a viscosity modifier; and defoamer.

In yet another aspect of this invention, a pourable glue formulation is provided. This pourable glue formulation includes a first urethane polymer, wherein the first urethane polymer is Sancure 898; a second urethane polymer, wherein the second urethane polymer is Sancure 777F; a compound operative to provide freeze-thaw stability to the formulation such as propylene glycol; an ester alcohol, wherein the ester alcohol is Texanol; a biocide, wherein the biocide is Acticide LA; a crosslinking agent, wherein the crosslinking agent is CoatOsil 1770 silane; a rheology modifier, wherein the rheology modifier is Acrysol RM-825; and a defoamer, wherein the defoamer is Surfynol DF-58.

Additional features and aspects of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the exemplary embodiments. As will be appreciated by the skilled artisan, further embodiments of the invention are possible without departing from the scope and spirit of the invention. Accordingly, the associated descriptions are to be regarded as illustrative and not restrictive in nature.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention are now described. Although the following detailed description contains many specifics for the purposes of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following embodiments of the invention are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention.

The present invention relates to an adhesive or glue formulation. In an exemplary embodiment of the present invention, a pourable glue formulation is provided. This pourable glue formulation includes a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; propylene glycol for conferring freeze-thaw stability to the glue formulation; an ester alcohol for conferring film-forming properties to the formulation; a biocide for preventing or at least limiting the growth of microorganisms in the formulation; a crosslinking agent for providing additional final strength to the formulation; a rheology modifier for providing a desirable final viscosity to the formulation; and a defoamer preventing or at least reducing any tendency of the formulation to foam during mixing of the ingredients therein (i.e., during the manufacturing process.

More specifically, in the exemplary embodiment, the first urethane polymer is Sancure® 898 (Lubrizol), which is an aliphatic waterborne urethane polymer that forms a very hard, flexible, clear, high gloss film upon drying, offers a high performance coating with very good stain, chemical and water resistance, and that provides good elongation at high tensile strength. The second urethane polymer is Sancure® 777F (Lubrizol), which is an aliphatic waterborne urethane polymer that offers very good abrasion resistance, provides high gloss and good shear stability, and that exhibits adhesion to a wide variety of substrates including nylon and polyester. Propylene glycol is used to confer freeze-thaw stability to the glue formulation, although other suitable stabilizers known to those of ordinary skill in the art are also compatible with this invention. Propylene glycol is an organic compound (a diol or double alcohol) with the formula C₃H₈O₂ and is a colorless, nearly odorless, clear, viscous liquid with a faintly sweet taste that is hygroscopic and miscible with water, acetone, and chloroform. The ester alcohol is Texonal™ (Eastman Chemical Company), which is a coalescent for latex paints typically used in the architectural, industrial, and maintenance markets. Texanol ester alcohol provides a high level of film integrity at low levels of coalescent. The biocide is Acticide® LA (Thor), which is a combination wet state biocide for water based products. Its active ingredients provide a wide spectrum of activity against both bacteria and fungi, including species that are difficult to control. This product is particularly effective against pre-existing contamination and is approved for use in craft products by the ACMI (Art & Creative Materials Institute, Inc.). The crosslinking agent is CoatOsil® 1770 silane (Momentive Performance Materials), which crosslinks under heat or at room temperature on alkaline substrates and that enhances waterborne coating performance, appearance and handling. The defoamer is Surfynol® DF-58 (Air Products), which is a silicone-based foam control agent useful in aqueous systems. It has strong foam control and de-aeration performance in water-based formulations. The viscosity or rheology modifier is Acrysol™ RM-825 (Rohm and Haas), which is a non-ionic, medium shear viscosity builder that can be used as a co-thickener in many types of formulations for attaining a desired balance of low and high shear viscosities.

Having generally described this invention, a further understanding can be obtained by reference to certain specific examples detailed below, which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified.

Example

In the exemplary embodiment, the various ingredients are present in the following percentages (by weight):

Sancure 898 (urethane polymer) 56.95 Sancure 777F (urethane polymer) 40.0 Propylene glycol 1.00 Texanol (ester alcohol) 0.25 Acticide LA (biocide) 0.10 Cotasil 1770 Silane 0.10 Surfynol DF-58 (defoamer) 0.10 Acrysol RM-825 (rheology modifier) 1.50 100.0

While the present invention has been illustrated by the description of exemplary embodiments thereof, and while the embodiments have been described in certain detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to any of the specific details, representative devices and methods, and/or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept. 

1) A pourable glue formulation, comprising: (a) a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; (b) a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; (c) a compound operative to provide freeze-thaw stability to the formulation; (d) a compound operative to confer film-forming properties to the formulation; (e) a compound operative to limit the growth of microorganisms in the formulation; (f) a compound operative to provide additional final strength to the formulation; (g) a compound operative to provide a desirable final viscosity to the formulation; and (h) a compound operative to prevent the formulation from foaming during mixing of the ingredients therein. 2) The formulation of claim 1, wherein the first urethane polymer is SANCURE
 898. 3) The formulation of claim 1, wherein the second urethane polymer is SANCURE 777F. 4) The formulation of claim 1, wherein the compound operative to provide freeze-thaw stability to the formulation is propylene glycol. 5) The formulation of claim 1, wherein the compound operative to confer film-forming properties to the formulation is an ester alcohol. 6) The formulation of claim 1, wherein the compound operative to limit the growth of microorganisms in the formulation is a biocide. 7) The formulation of claim 1, wherein the compound operative to provide additional final strength to the formulation is a crosslinking agent. 8) The formulation of claim 1, wherein the compound operative to provide a desirable final viscosity to the formulation is a rheology modifier. 9) A pourable glue formulation, comprising: (a) a first urethane polymer, wherein the first urethane polymer is operative to provide adequate tensile strength to the formulation; (b) a second urethane polymer, wherein the second urethane polymer is operative to provide adequate flexibility to the formulation; (c) a compound operative to provide freeze-thaw stability to the formulation; (d) an ester alcohol; (e) a biocide; (f) a crosslinking agent; (g) a viscosity modifier; and (h) a defoamer. 10) The formulation of claim 9, wherein the compound operative to provide freeze-thaw stability to the formulation is propylene glycol. 11) The formulation of claim 9, wherein the first urethane polymer is SANCURE
 898. 12) The formulation of claim 9, wherein the second urethane polymer is SANCURE 777F. 13) The formulation of claim 9, wherein the ester alcohol is TEXANOL. 14) The formulation of claim 9, wherein the biocide is ACTICIDE LA. 15) The formulation of claim 9, wherein the crosslinking agent is COATOSIL 1770 silane. 16) The formulation of claim 9, wherein the defoamer is SURFYNOL DF-58. 17) The formulation of claim 9, wherein the viscosity modifier is ACRYSOL RM-825. 18) A pourable glue formulation, comprising: (a) a first urethane polymer, wherein the first urethane polymer is SANCURE 898; (b) a second urethane polymer, wherein the second urethane polymer is SANCURE 777F; (c) a compound operative to provide freeze-thaw stability to the formulation; (d) an ester alcohol, wherein the ester alcohol is TEXANOL; (e) a biocide, wherein the biocide is ACTICIDE LA; (f) a crosslinking agent, wherein the crosslinking agent is COATOSIL 1770 silane; (g) a rheology modifier, wherein the rheology modifier is ACRYSOL RM-825; and (h) a defoamer, wherein the defoamer is SURFYNOL DF-58. 19) The formulation of claim 18, wherein the compound operative to provide freeze-thaw stability to the formulation is propylene glycol. 